Thread: Tahoe issue??
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Unread 02-07-2013, 05:28 PM
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if you have a phone take pictures of things you take of in stages and mac if you were close by i would came and fix it for you free off charge-- i do this for all my mates-- im sure there will be videos on you tube showing how to do it and maybe someone on here can video it and send it to you

your saying it runs rough on idle when cold and once its hot its good--yes it could be the throttle body blocked not allowing enough air at idle cause when the engine is cold the coolant temp sensor tells the computer the engine is cold so it alows injectors to stay open longer so if you not getting enough air due to a blocked throttle body it will run like have the choke pulled too hard on a carby engine

when you start the engine cold if you hold your foot on the gas just i tiny bit does it run better---


theres 3 things that can cause rough idle when cold

too much fuel
not enough air
vacum leak
head gasket leak or cracked head

i dont know too much about these engine and what they suffer from but they all work from the same princeable

with the crack head or gasket what happen when the car sits for long peroids water leaks back into one or more cylinders so when you start it will missfire till the water vapours are pushed out --once its hot the water that leaks in turns to a steam which dosent effect the cylinder just like old school water injection

there 2 ways i check for this
one--if its a v8 get 8 screw drivers remove all spark plugs while the engine is hot keep each spark plug in order to cylinder and check for difference in color of the spark plug usuall the one missfiring will look different colored --place a screw driver down each spark plug hole for 30 sec then remove one and check if there any water on the screw driver check all if there all dry then there no leaks

two you need some one who has a exhaust gas analizer --you remove the radiator cap you may need to empty some coolant from the radiator start the engine --place the probe in the radiator filler and cover with a rag and run the engine if you get a reading then you have exhaust gases on your cooling system
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